Directed and Undirected Songs in Free-Tailed Bats, Implications for Mammalian Vocal Production

Abstract

Event Abstract Back to Event Directed and Undirected Songs in Free-Tailed Bats, Implications for Mammalian Vocal Production Kirsten Bohn1, 2* and Michael Smotherman2 1 Florida International University, United States 2 Texas A&M, United States Most mammalian vocalizations are innate, inflexible and lack syntactical structure. Not surprisingly, the neurocircuitry of mammalian vocal production also appears relatively simple, being predominantly controlled by brainstem pattern generators. The Brazilian free-tailed bat, Tadarida brasiliensis, is unusual in that it is a mammal that sings like a bird – males produce hierarchically structured songs where specific syllables are combined to form phrases that vary in order and number from one rendition to the next. In songbirds it is known that song variability is generated by an avian analogue of the mammalian striatothalamic feedback pathway to cortex. To date, no mammalian vocalizations other than human speech are known to depend upon this striatothalamic pathway. If free-tailed bats can be shown to vary their songs in ways similar to songbirds, it may provide a unique example of how the striatothalamic circuitry contributes to mammalian vocal communication. The main goal of this project was to determine the contexts in which males sing and whether song flexibility varies with behavioral context. In the wild, males live in dense aggregations, usually in dark caves or crevices that preclude the use of visual cues. Given the environment in which singing occurs, we hypothesized that identifying the right auditory cues could be the key to characterizing batsong production. To test this, we conducted a set of playback experiments on a wild colony at Texas A&M that examined the relative effects of 1) echolocation calls that mimic a bat approaching the roost site and 2) unfamiliar male songs. We compared song responses to these two contextual stimuli with control periods of background noise. During playback experiments, we recorded 699 songs from an estimated 39 different males. Bats responded strongly and robustly to echolocation call stimuli – out of 50 sets of echolocation passes bats responded 74% of the time with 215 songs. During the same interval immediately preceding stimuli, bats sang only 6% of the time producing just three songs. Song responses were also incredibly rapid – initiating within 200 to 500 ms of stimulus onset. Song responses were highly specific to echolocation passes; bats did not respond to unfamiliar male songs even though there is no difference in the spectro-temporal structure of some song syllables and echolocation calls. Running the same experiments in our captive colony we found similar results – we rapidly triggered singing via playbacks of echolocation calls. Bats also sang in the absence of stimuli, but far less frequently. We labeled songs as directed songs if they were produced in response to an echolocation pass and undirected songs if they occurred during control periods. When we compared song structure between the two contexts we found a significant difference in song types and variability. Directed songs were significantly shorter and were more likely to contain buzzes than undirected songs. In conclusion, singing is rapidly triggered in free-tailed bats using echolocation calls and free-tailed bats vary songs across behavior contexts in a manner very similar to songbirds. Keywords: song, Mammal, Vocal-motor, bats, birdsong Conference: Tenth International Congress of Neuroethology, College Park. Maryland USA, United States, 5 Aug - 10 Aug, 2012. Presentation Type: Poster (but consider for Participant Symposium) Topic: Social Behavior Citation: Bohn K and Smotherman M (2012). Directed and Undirected Songs in Free-Tailed Bats, Implications for Mammalian Vocal Production. Conference Abstract: Tenth International Congress of Neuroethology. doi: 10.3389/conf.fnbeh.2012.27.00068 Copyright: The abstracts in this collection have not been subject to any Frontiers peer review or checks, and are not endorsed by Frontiers. They are made available through the Frontiers publishing platform as a service to conference organizers and presenters. The copyright in the individual abstracts is owned by the author of each abstract or his/her employer unless otherwise stated. Each abstract, as well as the collection of abstracts, are published under a Creative Commons CC-BY 4.0 (attribution) licence (https://creativecommons.org/licenses/by/4.0/) and may thus be reproduced, translated, adapted and be the subject of derivative works provided the authors and Frontiers are attributed. For Frontiers’ terms and conditions please see https://www.frontiersin.org/legal/terms-and-conditions. Received: 04 Jul 2012; Published Online: 07 Jul 2012. * Correspondence: Dr. Kirsten Bohn, Florida International University, Miami, FL, United States, bohnkirsten@gmail.com Login Required This action requires you to be registered with Frontiers and logged in. To register or login click here. Abstract Info Abstract The Authors in Frontiers Kirsten Bohn Michael Smotherman Google Kirsten Bohn Michael Smotherman Google Scholar Kirsten Bohn Michael Smotherman PubMed Kirsten Bohn Michael Smotherman Related Article in Frontiers Google Scholar PubMed Abstract Close Back to top Javascript is disabled. Please enable Javascript in your browser settings in order to see all the content on this page.